chmextract.c in the chmextract sample program, as distributed with libmspack before…
Priority LOW 30CWE-22Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- No fix listed
Attack profile from CVSS 3.0 · NVD. Fix status from CNA. Impact type from CWE-22 and the CVSS impact.
Summary
chmextract.c in the chmextract sample program, as distributed with libmspack before 0.8alpha, does not protect against absolute/relative pathnames in CHM files, leading to Directory Traversal. NOTE: the vendor disputes that this is a libmspack vulnerability, because chmextract.c was only intended as a source-code example, not a supported application
Why it matters now
EPSS 0.03284 88th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 5
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:kyzer:libmspack:0.3:alpha:*:*:*:*:*:* | 0.3 alpha | Vulnerable | Kyzer |
| cpe:2.3:a:kyzer:libmspack:0.4:alpha:*:*:*:*:*:* | 0.4 alpha | Vulnerable | Kyzer |
| cpe:2.3:a:kyzer:libmspack:0.5:alpha:*:*:*:*:*:* | 0.5 alpha | Vulnerable | Kyzer |
| cpe:2.3:a:kyzer:libmspack:0.6:alpha:*:*:*:*:*:* | 0.6 alpha | Vulnerable | Kyzer |
| cpe:2.3:a:kyzer:libmspack:0.7:alpha:*:*:*:*:*:* | 0.7 alpha | Vulnerable | Kyzer |
- cpe:2.3:a:kyzer:libmspack:0.3:alpha:*:*:*:*:*:* Versions 0.3 alpha Vulnerable ·Kyzer
- cpe:2.3:a:kyzer:libmspack:0.4:alpha:*:*:*:*:*:* Versions 0.4 alpha Vulnerable ·Kyzer
- cpe:2.3:a:kyzer:libmspack:0.5:alpha:*:*:*:*:*:* Versions 0.5 alpha Vulnerable ·Kyzer
- cpe:2.3:a:kyzer:libmspack:0.6:alpha:*:*:*:*:*:* Versions 0.6 alpha Vulnerable ·Kyzer
- cpe:2.3:a:kyzer:libmspack:0.7:alpha:*:*:*:*:*:* Versions 0.7 alpha Vulnerable ·Kyzer
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 2 products
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
Timeline
- 2026-10-02 Threatist record created from CVE-2018-18586
- 2026-10-03 Alias added: GHSA-jcvf-2rhc-m6h8
References
More Kyzer Libmspack vulnerabilities
- TI-2019-16069 Memory corruption in libmspack CVSS 3.1MEDIUM 5.5
- TI-2018-13145 chmd_read_headers in mspack/chmd.c in libmspack before 0.8alpha accepts a filename that… CVSS 3.1MEDIUM 4.3
Sources
- CVE-2018-18586 · CVE Program
- CVE-2018-18586 · NVD
- FIRST EPSS
- GHSA-jcvf-2rhc-m6h8 · GitHub Advisory Database · CC BY 4.0
- CVE-2018-18586 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences